There will be described an aluminum electric wire connecting structure disclosed in a patent literature 1, by using FIGS. 12 to 16. As shown in the figures, there is a connector 2 having a connecting portion 3 and a crimping portion 4, the connecting portion 3 being integral with the crimping portion 4. The connecting portion 3 as well as the crimping portion 4 is made of copper. The connecting portion 3 is connected to a terminal of a device, for instance. The crimping portion 4 is provided with projections 5 at an inner surface thereof. The projections 5 are formed in a shape of a quadrangular pyramid having a tip part thereof cut off substantially in parallel to a bottom side, so the projections 5 have a combination of four inclined sides 6 triangular in shape. The inclined sides 6 have an inclination angle θ within a range of 45 to 75 degrees relative to areas of surface 8 on the crimping portion 4 each surrounded by a set of four projections 5. At the connector 2, the crimping portion 4 is crimped on a terminal portion of a solid aluminum electric wire 1. As shown in FIG. 16, the crimping portion 4 is formed in a substantially elliptical shape.
This aluminum electric wire connecting structure has sets of projections 5 provided at the crimping portion 4 and pressed into areas of surface of the aluminum electric wire 1, so as shown in FIG. 17, the aluminum electric wire 1 has distorted regions 7 formed as illustrated by two-dot chain lines in surface regions thereof. Further, as will be seen from FIG. 14, at each area of surface 8, four surrounding projections 5 each have inclined sides 6 thereof each opposing another inclined side 6. For this reason, as shown in FIG. 17, distorted regions 7 each have a combination of a local region 7a thereof extending along an inclined side 6a in opposition to a local region 7a thereof extending along an inclined side 6a. Accordingly, at each distorted region 7, there can be cold flows developed from local regions 7a thereof and stopped by other local regions 7a thereof, thus allowing for an ensured stopping of cold flow. As a result, at each distorted region 7, stresses to be relaxed by cold flows can be suppressed, affording to suppress deteriorations in crimp strength (or adhesive force) between the aluminum electric wire 1 and inclined sides 6 of projections 5. Therefore, between the aluminum electric wire 1 and the crimping portion 4, electric resistances to be increased can be suppressed.